1// spreadsort on a mostly sorted array example.
2//
3// Copyright Steven Ross 2009-2014.
4//
5// Distributed under the Boost Software License, Version 1.0.
6// (See accompanying file LICENSE_1_0.txt or copy at
7// http://www.boost.org/LICENSE_1_0.txt)
8
9// See http://www.boost.org/libs/sort for library home page.
10
11#include <boost/sort/spreadsort/spreadsort.hpp>
12#include <time.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <algorithm>
16#include <vector>
17#include <string>
18#include <fstream>
19#include <sstream>
20#include <iostream>
21using namespace boost::sort::spreadsort;
22
23#define DATA_TYPE int
24
25unsigned
26get_index(unsigned count)
27{
28 unsigned result = unsigned((rand() % (1 << 16))*uint64_t(count)/(1 << 16));
29 if (result >= count || result < 0)
30 result = count - 1;
31 return result;
32}
33
34//Pass in an argument to test std::sort
35int main(int argc, const char ** argv) {
36 srand(seed: 1);
37 size_t uCount,uSize=sizeof(DATA_TYPE);
38 bool stdSort = false;
39 unsigned loopCount = 1;
40 for (int u = 1; u < argc; ++u) {
41 if (std::string(argv[u]) == "-std")
42 stdSort = true;
43 else
44 loopCount = atoi(nptr: argv[u]);
45 }
46 //Sorts the data once, then times sorting of already-sorted data
47 loopCount += 1;
48 std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
49 if (input.fail()) {
50 printf(format: "input.txt could not be opened\n");
51 return 1;
52 }
53 double total = 0.0;
54 std::vector<DATA_TYPE> array;
55 input.seekg (0, std::ios_base::end);
56 size_t length = input.tellg();
57 uCount = length/uSize;
58 input.seekg (0, std::ios_base::beg);
59 //Conversion to a vector
60 array.resize(new_size: uCount);
61 unsigned v = 0;
62 while (input.good() && v < uCount) // EOF or failure stops the reading
63 input.read(s: reinterpret_cast<char *>(&(array[v++])), n: uSize );
64 //Run multiple loops, if requested
65 for (unsigned u = 0; u < loopCount; ++u) {
66 for (unsigned v = 0; v < uCount/10; ++v)
67 std::swap(a&: array[get_index(count: uCount)], b&: array[get_index(count: uCount)]);
68 clock_t start, end;
69 double elapsed;
70 start = clock();
71 if (stdSort)
72 //std::sort(&(array[0]), &(array[0]) + uCount);
73 std::sort(first: array.begin(), last: array.end());
74 else
75 //integer_sort(&(array[0]), &(array[0]) + uCount);
76 integer_sort(first: array.begin(), last: array.end());
77 end = clock();
78 elapsed = static_cast<double>(end - start) ;
79 std::ofstream ofile;
80 if (stdSort)
81 ofile.open(s: "standard_sort_out.txt", mode: std::ios_base::out |
82 std::ios_base::binary | std::ios_base::trunc);
83 else
84 ofile.open(s: "boost_sort_out.txt", mode: std::ios_base::out |
85 std::ios_base::binary | std::ios_base::trunc);
86 if (ofile.good()) {
87 for (unsigned v = 0; v < array.size(); ++v) {
88 ofile.write(s: reinterpret_cast<char *>(&(array[v])), n: sizeof(array[v]) );
89 }
90 ofile.close();
91 }
92 if (u)
93 total += elapsed;
94 }
95 if (stdSort)
96 printf(format: "std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
97 else
98 printf(format: "spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
99 return 0;
100}
101

source code of boost/libs/sort/example/mostlysorted.cpp